Automatic self-closing wrench



July 19, 1955 J. v. LARSON w 2,713,280

AUTOMATIC SELF-CLOSING WRENCH Filed NOV. 16, 1951 2 Sheets-Sheet l 6 mg A It, as

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[6i Q W July 19, 1955 J. v. LARSON 2,713,280

AUTOMATIC SELFCLOSING WRENCH Filed Nov. 16, 1951 2 Sheets-Sheet 2 United States Patent 2,713,234 Patented July 19, 1955 fiice all AUTOMATIQ SELF-CLOSING "WRENCH John V. Larson, Chicago, Ill.

Application 1. ovemher 16, 1951, Serial No. 256,650

2 Ciaims. (Cl. 81-99) This invention relates to hand tools and more particularly to self-adjusting pipe wrenches, although certain features thereof may be employed with equal advantage for other purposes.

It contemplates more especially the provision of improved hand tools of the pipe wrench type embodying self-closing expedients comprising the subject matter of United States Letters Patents 1,602,620, 1,830,033 and 2,351,821 which have been simplified in their construction to improve their operation and effectiveness, increase the capacity and to substantially reduce the manufacturing costs thereof.

One object of the present invention is to simplify the construction and improve the operation of devices of the general character mentioned.

Another object is to provide an improved pipe wrench that has a more effective jaw structure and an improved spring structure that makes the wrench self-adjusting to the work that is to be turned thereby.

A further object is to provide an improved combination pipe and nut turning wrench of the self-adjusting thumb trigger actuating type possessing effective gripping action and having a reinforcing pivot providing appreciable load capacity.

Still a further object is to provide an improved pipe wrench gripper element and reinforcing pivot assembly which effectively serves as a combination pipe and nut turning device light in weight and having an appreciable load capacity.

Ari additional object is to provide a light weight metal wrench having an improved reinforcing jaw pivot construction for increased load capacity.

Gtber objects and advantages will appear from the following description of an illustrated embodiment of the present invention.

In the drawing:

Figure l is a side view in elevation of a pipe wrench embodying features of the present invention.

Figure 2 is an edge view of the pipe wrench shown in Figure I, viewed from the open jaw side thereof.

Figure 3 is a fragmentary side view in elevation of the jaws with parts thereof broken away and shown in section to clarify the illustration.

Figure 4 is a fragmentary top edge view of the wrench jaw structure shown in Figures 1 to 3 inclusive.

Figure 5 is a fragmentary perspective view of the fixed jaw and shank illustrated in Figures 1 and 3.

Figure 6 is a perspective view of the fixed jaw serrated engaging and gripping element which is detachable for ready replacement.

Figure 7 is a side view in elevation of a modified movable jaw assembly similar to the embodiment assembled in Figures 1 and 3 but modified to eliminate the removable pin bearing shown in the preferred embodiment in Figures 1 to 6 inclusive, parts thereof being broken away and shown in section to clarify the showing.

Figure 8 is a perspective view of the movable jaw serping surface thereof.

2 rated engaging or gripping element detachably associated with the movable jaw of both embodiments.

Figure 9 is a sectional view of the movable jaw assembly taken substantially along line IX-IX of Figure 7.

Figure 10 is an edge view of a spiral spring shown assembled in Figures 1, 3 and 7.

Figure 11 is an elevation of the inner side of the fixed jaw and spring cover plate.

Figure 12 is a fragmentary elevation of that side of the fixed jaw complemental to the cover plate shown in Figure 11. I

Figure 13 is a fragmentary edge view of the separable elements comprising the head or jaw part of the modified wrench without the removable pin bearing and with the complemental elements shown in spaced related positions preparatory to assembly.

The structure selected for illustration is not intended to serve as a limitation upon the scope or teachings of the invention, but is merely illustrative thereof. There may be considerable variations and adaptations of all or part of the teachings depending upon the dictates of commercial practice.

The illustrated embodiment comprises an elongated wrench handle 10 that is forged or cast from an alloy steel or aluminum composition to present a somewhat tapered manipulating shank. The handle shank 10 has rounded transversely extended integral webs 11, 12 formed near the free end thereof to terminate in an enlarged oblong boss 13 presenting a lobe 14 to prevent slipping of the hand from the handle 10. The oblong boss 13 is offset from the handle 10 to provide the obstructing lobe 14 through which an elongated hole 15 is provided to lighten the construction and to permit the wrench to be hung from a suitable vertical wall anchor such as a nail.

The shank it) tapers outwardly or diverges slightly as at 16 to terminate in a fixed or stationary jaw 17 that has an enlarged angular straight end surface 18 provided with a rectangular recess 19 to receive a complementary cleat 2!) formed integral with an arcuate detachable jaw gripper element 21 (Figure 6). The arcuate surface of the jaw gripper element 21 is provided with serrations or teeth 22 over the entire grip- The gripping serrations 22 are formed on a rectangular base member 23 to which the cleat is anchored or formed integral therewith. Transverse apertures 24, 25 are provided in the sides of the stationary jaw 17 to register with an aperture 26 provided through the gripper cleat 20 for receiving a retainer pin 27 therethrough. The fixed or stationary jaw 17 projects from a somewhat enlarged well rounded boss 28 formed at its jointure with the handle shank 10 to serve as a pivoting expedient for a movable jaw 29. The enlarged rounded jaw boss 28 is integral with the handle 10 and lies opposite an enlarged jaw boss formed as part of a detachable cover plate 29 having linearly aligned apertured cars 30, 31 through which threaded screws 32 extend for threaded attachment to the handle 14) and fixed jaw 17. To this end, the handle 10 and fixed jaw 17 have threaded apertures 33, 34 (Figure 12) for threadedly receiving the fasteners 32.

The cover plate 29 is provided with a cup-shaped recess 36 which confronts an elongated recess 37 formed in the handle member shank 16 and the fixed jaw 17 regions thereof. The recess 37 is closed on its lower side by a flange forming a seat for the cover plate 29, and extends between the upper edges of the handle shank 16 and cover plate 29 to provide a guide opening for the pivotal displacement of the movable jaw 29'. The movable jaw 29 pivots about a pivot pin 38 fitted in aligned apertures 39 and 49 provided in the complemental fixed u jaw or handle shank 16 and the cover plate 29. The support and retention of the pivot pin 38 is effected by a nut41 engaging a threaded end 42 of the pin 38.

It should be noted that the recess 36 is substantially circular, and that the pivot apertures 39 and 40 are disposed axially of said recess. A spiral spring 43 having an inwardly offset inner extremity 44 and an outwardly offset outer extremity 45, is mounted on an axial boss 46 comprising part of a circular bracket end 47 formed integral with the end'of the movable jaw 29'. An aperture 48 extends axially through the boss 46 and its bracket 47 to receive the pivot pin 38 for pivotally mounting the movable jaw 23 that is substantially a wide U-shaped shank member in which the circular bracket 47 comprises one arm, and a gripping jaw 49 comprises the other arm.

In order to provide self-closing movement of the movable jaw 29',toward the stationary jaw 17 in a clockwise direction (as viewed in Figure 3), the inwardly offset spring extremity 44 registers with one of two radial slots 50, 51 (see Figure 7) provided in the upraised boss 46 of the movable jaw 29' while the outwardly offset spring extremity 45 registers with and engages a recess ofiset 52 pro-' vided proximate to the cover plate fastener hole 34 in communication with the recess 37 in the stationary jaw 17 (Figure 12). The registry of the inner spring end id in one or the other of the radial slots 50, 51 provides an adjustable spring tension to compensate for variations in spring characteristics or to provide the desired movable jaw closing urge for any particular user.

It is to be noted that the movable jaw 29 has a well.

rounded or curved exterior edge 53 extending from the thinner pivotal shank arm 47 to and around the confronting arm 49 thereof; and this rounded and curved edge 53' merges with a comparatively wider straight fiat inner gripper face 54 defined by edge reinforcing ribs 55, 56. The edge reinforcing ribs 55, 56 extend around the confronting arm 49 of the movable jaw 29' to provide an enlarged angularly disposed straight surface 57. The straight angularly disposed jaw engaging surface 57 is rectangularly recessed as at 58 (Figure 7) like the recess 19 (Figure 5) in the stationary jaw surface 18 to receive the complemental cleat 59 of a straight serrated detachable gripping element 60 (Figure 8).

The gripping element 69 has its cleat 59' transversely apertured as at 61 to register with aligned apertures 62 provided in the movable jaw arm 49 through the reinforcing edge ribs 55, 56 thereof to receive a gripping element retainer pin 63. Consequently, the stationary and movable gripping elements 21, 60 ar readily replaceable, and confront each other in a variety of angles to effectively grip articles such as pipes 64 of different diameters therebetween. .In order to thumb actuate the movable to 'its desired open initial position against the closing urge of the spring 43, the rounded back edge 53 of the movable jaw 29' terminates rearwardly in a smooth- 'ly curved projecting thumb trigger extension or rest 65 at the juncture of the movable jaw 29 with its comparatively thinner pivotal shank arm 47. It should be noted that the movable jaw closing spring 43 is assembled on the boss 46 of the pivotal shank arm 47, and the outwardfy ofiset spring end 45 is lodged into its engaging recess 52 of the stationary jaw 17 (Figure 12) before the pin 38 is assembled and the cover plate 29'attached and secured in position by means of the threaded fasteners 32.

The detachable arcuate and serrated gripping element '21'on the fixed or stationary jaw 17 (Figures 1 and 3) confronts the detachable angular gripping element 60 on the movable jaw 29, and these are made from high carbon steel which is hardened to provide maximum wear.

Besides being more durable than the remaining structural parts, these gripping elements 21, 66 (Figure 3) are detachable for ready replacement to give extended life to the wrench structure. This replacement is rendered possible by the pin retained cleats 29 and 59 on the gripping elements 21, 60, respectively. With this arrangement, any user may easily knock out or replace the gripping elements 21, 60. It should be noted that the gripping eleroents 21, 60 may be varied in shape and structure depending upon the dictates of commercial practice.

by thumbing the trigger extension 65 in a clockwise direction (as viewed in Figure 1) the jaws 17, 29' can be readily opened to accommodate the work that is to be turned. Thurnbing the trigger 65 in a counter-clockwise direction (as viewed in Figure 1), serves to increase the gripping action or to initiate the gripping action and procure more efiective results. The concave and extended thumb-engaging surface of the trigger 65 provides an extended surface which facilitates thumb manipulation of the movable jaw 29' without inconvenience or abrasion to the thumb. Also, the attendant can thumb the trigger 65 in a clockwise direction (as'viewed in Figure l) to open the movable jaw 29 relative to the stationary jaw 17 to any desired distance within the limit defined by the shoulder formed on the movable jaw 29' along an edge from which the trigger 65 extends (Figure '3). This shoulder engages the handle and jaw shank 16 in the extreme open position of the movable jaw 29 relative to the stationary jaw 17 (Figure 3).

it should be noted that in making the handle 10 and its associated parts except for the gripper elements 21, 60 from aluminum alloy, an extra steel reinforcing pin bearing 66 is compositely associated with the comparatively lighter but essentially weaker handle 19 which may be cast, forged or otherwise shaped from aluminum or aluminum alloy. Such light metals have desirable characteristics but do not normally possess the strength to carry appreciable loads in the region of the steel pin 38. To this end, the pin bearing 66 is provided with an axial bore 67 therethrough'to freely receive the pin 38, and the exterior of the pin bearing 60 is preferably provided with circumferentially spaced radial ribs 68, in this instance six, which provide a retaining medium for the stationary jaw 17 which is cast or otherwise shaped from aluminum or similar materials with the pin bearing 66 in position.

With this expedient, the pin bearing 66 may be compositely associated therewith in the region for the reception of the pin 38 therethrough, thereby precluding the pin bearing 66 from rotating relative to the handle 10 and stationary jaw 17.

The steel pin bearing 66 will appreciably increase the load bearing capacity of the comparatively lighter, and weaker aluminum alloy handle 10, and all the advantages of a steel Wrench are procured with the additional desirable feature of having an appreciably lighter wrench. The spring 43 is assembled therewith in the manner described supra, and by providing hardened high carbon steel gripping elements 21, 60 illustrated and described in connection with Figures 1 and 5, a very desirable and satisfactory light weight wrench results. It should also be noted that wrenches of this character may be cast or otherwise shaped from beryllium which assures adequate strength and provides a safe non-sparking tool that wiil meet the specifications and service requirements of oil refineries and other industries where highly ,in-

flammable substances are involved and cannot, therefore, be exposed or subjected to any possible spark.

With the arrangement of parts and structural features described above, it will be apparent that the movable jaw 29 that confronts the stationary jaw 17 accommodates both round and polygonal shapes so that the modification without departing from the function of the invention. 1, therefore, do not wish to be limited to the precise details of construction set forth, but desire to avail myself of such variations and modifications as come within the scope of the appended claims.

I claim:

1. A hand tool comprising an elongated handle member, a fixed jaw formed on said handle member, a movable jaw pivoted to said handle member in confronting relation with said fixed jaw, a pivot pin extending through said movable jaw and handle member to pivotally mount said movable jaw relative to said fixed jaw, a circular boss on said movable jaw to surround said pivot pin, and spiral spring means associated with said confronting jaws to normally urge said movable jaw toward said fixed jaw, an inner end of said spiral spring means being adjustably anchored to said circular boss proximate to but offset from said movable jaw pivot, an outer extremity of said spring being anchored to said fixed jaw for normally urging the movable jaw toward said fixed jaw, there being radial slots in said circular boss on said movable jaw member to selectively receive the inner end of said spring, said boss being axially mounted relative to said pivot pin, and said spring outer extremity and inner end comprising ofisets for detachable connection with said fixed and movable jaw.

2. A hand tool comprising an elongated handle memher, a fixed jaw formed on said handle member, a movable jaw pivoted to said handle member in confronting relation with said fixed jaw, a pivot pin extending through said movable jaw and handle member to pivotally mount said movable jaw on a fixed axis, a boss on said movabie jaw surrounding said pivot pin, said boss having radial slots therein, and a spiral spring surrounding said boss to normally urge said movable jaw toward said fixed jaw, an offset on an inner end of said spring being anchored in one of the radial slots in said boss, and an offset on an outer extremity of said spring being anchored to said fixed jaw.

References Cited in the file of this patent UNITED STATES PATENTS 295,204 Schramm et al. Mar. 18, 1884 329,221 Schramm Oct. 27, 1885 676,318 Jackson June 11, 1901 1,317,808 Mohr Oct, 7, 1919 2,388,622 Stewart et al. Nov. 6, 1945 2,397,770 Adams Apr. 2, 1946 2,464,555 Carnelli Mar. 15, 1949 2,559,974 Kunz July 10, 1951 2,645,145 Larson July 14, 1953 FOREIGN PATENTS 126,024 Australia Nov. 20, 1947 

